The invention relates to a method for adapting, as a function of the driving situation and driving style, the side support of a person sitting in the seat of a vehicle, in particular of a passenger car, in which a lateral acceleration acting on the seat is determined as a reference variable for the adaptation, as well as to a vehicle seat with an adaptive side support system.
In a known vehicle seat of the above-mentioned type, such as is disclosed in German Patent document DE 35 05 088 C1, inflatable cushions are formed into the upholstery of the vehicle seat for individually supporting, in particular, the back of the sitting person. Inflatable side cushions are also inserted into the edge areas of the seats for providing adjustable side support. The variable air pressure in the air cushions is set by means of a pressure regulating device. The pressure which is set is fed to the respective air cushions by means of a pressure distribution device. A sensor which generates a signal when there is a prespecified absolute value of the lateral acceleration acting on the vehicle seat causes, when it responds and the side support is not switched on, the side cushions to fill up to a predetermined value. The air cushion control is carried out by means of solenoid valves which vent the cushions in their basic position, and in their working position apply a prespecified air pressure to them from the pressure regulating device.
In this known vehicle seat, the side support is therefore actuated only if the lateral acceleration acting on the seat exceeds a prespecified value, the activation taking place simultaneously in the two edge areas of the seat. The applied support which is set here by pressurizing the side cushions is always configured identically irrespective of the absolute value of the lateral acceleration. If the lateral acceleration drops again below this prespecified value, the side support is eliminated automatically by venting the side cushions.
In a vehicle seat which is likewise known, such as from German Patent document DE 35 41 537 A1, when the vehicle is turning the driver is supported counter to the lateral or transverse acceleration which occurs during such turning in that one of two supporting bellows which are provided laterally in the seat is quickly filled with compressed air if the lateral acceleration exceeds a specific value. In order to determine the lateral acceleration, a control sensor which is arranged in the steering column of the vehicle and a vehicle speed sensor are provided. A processor calculates from the relationship between the control angle of the steering column supplied by the control sensor and the vehicle speed supplied by the vehicle speed sensor, the maximum lateral acceleration occurring during the turning maneuver. If this previously calculated lateral acceleration exceeds a prescribed value, the corresponding supporting bellows are suddenly filled with compressed air.
These known vehicle seats accommodate the desire of many drivers (who prefer a less sporty driving style but, at the same time, demand high levels of seating comfort) for side support which occurs only in specific driving situations, for example in the case of extreme cornering, even though at the same time it adversely affects seating comfort. Investigations have shown that at relatively low speed drivers accept relatively large lateral accelerations without desiring side support, but at a high speed drivers find side support pleasant even when the lateral acceleration is small, but the side support should then preferably only take place on one side, that is on the side of the seat which is on the outside of the turning curve.
The invention is based on the object of specifying a method for adapting the side support as a function of the driving situation and driving style, and for specifying a vehicle seat with such a side support. The method and seat make greater allowance for the ways in which drivers or vehicle occupants sense the lateral acceleration, and thus combine a comfortable sitting sensation with the advantages of the necessity for side support which is established in bends (curves) at short notice.
This and other objects are achieved according to the invention by a method for adapting the side support, as a function of the driving situation and driving style, of a person sitting in the seat of a vehicle, in particular of a passenger car, in which a lateral acceleration acting on the seat is determined as a reference variable for the adaptation. The determined lateral acceleration is weighted with the instantaneous driving speed of the vehicle and a control variable for the degree of adaptation is derived therefrom. A corresponding vehicle seat according to the invention has a seat component and a backrest, as well as an adjustable side support. The side support is formed in the seat component and/or in the backrest, for the sitting person, and has a control unit which performs the adaptation of the side support as a function of a lateral acceleration acting on the seat. The control unit generates a control variable which determines the degree of adaptation from the instantaneous lateral acceleration (b.sub.Q) and the instantaneous driving speed (v) by using a stored weighting algorithm which describes the relationship between the driving speed (v) and the lateral acceleration which is perceived by the sitting person.
The method and the vehicle seat according to the invention have the advantage that by taking into account the vehicle speed during the generation of the control variable for the side support, which is preferably on one side of the seat, the vehicle seat gradually adapts automatically to the lateral acceleration which is sensed or perceived by the driver as a function of a particular driving situation. Thus, the advantages of a comfortable seat, combined with the advantages of a sport-type seat, are made available to the sitting person. The adjustment of the sitting properties takes place automatically and does not distract the driver from the events on the road.
Expedient embodiments of the method and vehicle seat according to the invention with advantageous developments and improvements of the invention are described herein.
According to one preferred refinement or embodiment of the invention, the driving style of the driver is classified and a supplementary control variable which is superimposed on the control variable is derived from the result of the classification. The classification of the driving style is carried out as described in German Patent document DE 44 01 416 A1, for example. In this method, the driving style is characterized gradually between steady and dynamic. The sitting comfort of the vehicle seat and the sitting sensation of the occupant are also additionally automatically adapted to the current driving style. A sporty, dynamic driving style then leads automatically to side support being provided on both sides of the seat, whereas in the case of a steady driving style the side support on both sides is eliminated. Classification results of the driving style classification which lie in between these styles lead to a greater or lesser degree, i.e. a more or less perceptible degree of side support on both sides.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.